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15600 Harlan Road, Lathrop <br /> Page 2 t <br /> The EHD provides the following comments and conditions on the work.pian:. <br /> R <br /> 1. 'Section 2.3, Contaminant Distribution discusses MTBE impact t i <br /> groundwater in Sand.B evidenced;by samples from MW8 that is northwest. <br /> of the former UST location. MW8 is northeast of the farmer UST location <br /> and the observed pattern of contaminant migration has been to the: <br /> northeast of the former UST location not to the northwest. It also states <br /> that Sand zone-C has not been investigated. The allay 2004 CPT <br /> f investigation indlOded"investigation of the Sand C zone. At that time no <br /> contamination was found in Sand,C. Unfortunately, the contamination <br /> has continued to migrate so further investigation of Sand C is.now <br /> required:. <br /> 2.; Collection and analysis Of grab groundwater samples from rnohitoring <br /> wells installed northwest of MW2 and northwesterly of MUUG3.is not <br /> approved as adequate-or necessary by EHD nor is `in601.1atio.mof <br /> :additional Its based on those grab water sample:results approved as <br /> adequate and necessary by EHD. <br /> 3, The soil boring for the Sand C'monitoring well installation In the area of <br /> MW8 and MW9 should be continuously cored below 40feet to decide on <br /> the interval.for the well screen. The soil borings for the Sand B monitoring <br /> well installations northeast of MW 1`1*and northwesterly of MWO3 should <br /> be aantinuou lyscored to decide on the interval for those vvell screens;. <br /> 4. The length of the well screens in the Sand B.and Sand C;monitoring wells <br /> should be a maximum:of 16.feet. The length of the W li sereen far Sand <br /> A monitoring â–ºnrells should be 15 to 2,0 feet based on lithology. <br /> $entonite p+silets are not acceptable grout seals. Bentonite pellets can.be <br /> used as a transition between sand pack and neat cement or <br /> pernentlbentonite grout seats. On the.shallow monitoring wells there may <br /> be a small grout seal but on the deeper monitoring wells there should be a <br /> significant grout seal. New well diagrams are to be.submitted to EHD as k <br /> an addendum-to the work plan that show proper well construction details <br /> prior to scheduling the work. <br /> £., The latitude and longitude of all the newly installed monitoring wells <br /> accurate to within 1 meter and referenced to a minimum of two reference <br /> points from the CSRS-H:_must be obtained and submitted to Geo#racker <br /> (the State Water Resources Control Board internet database system). In' <br /> addition, the newly installed monitoring wells must be surveyed to sea <br /> level and this information must be submitted to Ceotracker. <br /> 7. All laboratory data, groundwater levels, boring lags and reports must also <br /> be submitted to Geotracker. <br /> 8. A completed EHD well permit application, $89 permit fee and $285 <br /> inspection fee must be submitted for each parcel or public right of way to <br /> be drilled upon. 'An encroachment permit from the appropriate public <br /> agency or an access agreement from the off-site property owner must be <br /> submitted prior to EHE issuance of those permits. <br /> 9. Provide EHD at least 48 hours notice prior to work being performed so <br /> that:inspections can be scheduled., <br /> ;t <br />